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Weather and Your Health

By Joe D'Aleo
Monday, October 12, 2009

Since ancient times, people have made a connection between weather and health. Hippocrates first wrote about the affect of hot and cold winds on people and the possible connection between epidemics and weather conditions in 400 BC. These ideas were further developed by herbalists in the Middle Ages, who prescribed specific plants for use during the different winds. Many of these ideas were discarded as "folk medicine" with the rise of empirical science, and lacking in scientific basis. Centuries later, medical science began a series of experiments that led to a revived interest in the connection between weather and health.

In 1877, S.Weir Mitchell, a Philadelphia doctor wrote an article in the prestigious American Journal of Medical Sciences on "The Relation of Pain to Weather". The article related the onset and degree of pain recorded in a log by a Union Captain, whose leg had been amputated after a Civil War injury, to local weather conditions. He observed that the pain began as pressures fell and humidity and temperatures rose, conditions usually associated with an approaching storm. He noted the pain continued until the pressures began to rise and humidities began to fall as the storm departed.

Seventy years later in Germany, another very similar study confirmed this relationship and really kick-started a new science, called Biometeorology. Formed from the two Greek words "bios" meaning life and meteoros meaning "the study of phenomena up above (thus weather phenomena in the atmosphere)". The new science studied the effect of weather on life (health).

This time the two players were Otto Hollich, a PhD student at the University of Hamburg and Claus Thurkow, a German soldier. Claus had lost an arm in 1945 after heavy shrapnel injury suffered in World War II. He kept a detailed daily log of the onset, degree and duration of pain for five years while the meteorology student tracked the daily weather. The meteorology student used more sophisticated statistical methods than the earlier study but the results were very much the same. He noted that the pain began when pressure fell and humidities rose, the first sign of an approaching storm. The research showed the pain continued until the storm and cold front finally passed, pressures began to rise and temperatures and humidities began to fall.

The pain and weather relationship has since been established beyond reasonable doubt from further controlled studies. After that study, much additional research in both the US and abroad has since established elationships between many ailments and weather conditions. The Germans have taken a world lead in this ew discipline. The German meteorological service for years now have provided daily advice and advisories to hospitals, doctors and clinics in Germany on which ailments are likely to be aggravated due to expected weather conditions.

In this country, the principle proponent of the science of Biometeorology was the late Helmut Landsberg, Professor at the University of Maryland and the father of modern
Climatology. He catalogued many ailments and their weather connection in the landmark book "Weather and Health, An Introduction to Biometeorology" (Doubleday 1969).

Some of the weather and health connections include:


Air Stagnation
Aches And Pains
Respiratory Distress
Extreme Temperatures
Influenza Report
Reflexes/Reaction Times

Attentiveness/Mental Alertness

Labor And Birth Index· 

UV Report
Mood Index/Depression (Sad)
Indoor Relative Humidity
Allergen Report

Cardiovascular Distress 

Air Stagnation

High levels of air pollution can cause marked increase in sickness and even deaths. Lower, less acute pollution can be harmful to health. Many medical and scientific studies in recent years have shown positive relationships between air pollution and increases in respiratory ailments and heart disease. The risk is greatest for the very old, very young and people already suffering with certain chronic ailments such as emphysema.

Air pollution can become a problem when air stagnates (gets trapped) in a region due to atmospheric conditions. Air stagnation occurs when and where air may be trapped by poor ventilation (persistent light or calm winds) and the presence of inversions. When air stagnation persists in a region, pollution can accumulate resulting in increasingly poor air quality.

Air pollutants can irritate the respiratory system, causing a large increase in mucous secretions by the body, which may impair breathing. Also the release of histamines and allergic reactions.

Air pollution episodes especially if fog is present can cause more damage as gases like sulfur dioxide can react with the water droplets in the air to produce a damaging combination - sulfuric acid mist. This can cause permanent damage for even healthy individuals.

This was a greater problem in the days when we burned coal and other high sulfur fuels. The great air pollution fog in London in December 1952 was said to have killed 4,000. In Donora, Pennsylvania an "Indian Summer" smog and fog event in 1948 lasted for nearly a week, killing 19 and affecting 43% of the population.

Aches & Pains Index

Weather sensitive individuals with certain ailments such as arthritis and rheumatism can have those ailments aggravated by certain weather conditions. Damp and chilly weather, rising humidity, rapidly falling barometric pressure and gusty winds produce the greatest effects.

These conditions are observed to cause a swelling of the joints. It may be the membranes in the joint act as a barometer and expand as the air pressure drops. This can cause an increase in pressure of the fluids that lubricate the joint. This then offers more resistance to movement and increases the pains in those joints already compromised.

Respiratory Distress

Weather sensitive individuals with chronic respiratory ailments like emphysema and bronchial asthma can be acutely impacted by certain weather conditions. In addition to air pollution episodes, respiratory distress is greatest during sudden cold outbreaks with rapidly falling, much below normal temperatures, strong and gusty winds, and rapidly rising pressures.

The sudden change to cold temperatures can cause bronchial spasms, which restrict the airways and hamper breathing. Strong winds can raise dust and dirt into the air and further irritate the respiratory system.

It should be noted that the first such cold outbreaks seem to have the greatest affect on illness, with the largest increase in hospital admissions. You should ensure you have your prescriptions filled in advance when the four-day forecast shows a big change to colder temperatures is approaching. You should carry those medications with you on those high problem days. Parents should make sure their children with asthma have their medications (e.g. inhalers) with them when they wait for the school bus or walk to school on those first blustery and cold fall or winter mornings.

Extreme Temperatures

Extreme cold and/or the combined effect of cold and wind can cause hypothermia or frostbite in individuals not properly protected by clothing. You are advised to use layers of warm clothing and to protect extremities when exposed to extreme cold for extended periods.

Extreme heat and/or the combined effect of heat and humidity can cause heat exhaustion and in the extreme, Heat Stroke or Hyperthermia. In the hot weather, you are encouraged to avoid strenuous exercise, avoid direct sunshine where possible and to drink plenty of fluids.

The body's regulatory system is stressed beyond its ability to cope with the environmental

extremes. In the cold, it is not able to produce or conserve heat to maintain a steady internal body temperature. In the extreme heat it may be unable to dissipate heat produced internally through the mechanisms available to it (through the skin to the air or through evaporative cooling of moisture (sweat). Or the moisture needed for the needed evaporative cooling may be lacking (dehydration)

It should be noted that great extremes of temperature are not always needed to cause these problems. Improper dress and prolonged exposure under more moderate conditions can lead to problems. For example, temperatures a few degrees below freezing in a strong wind may cause frostbite in a child, who is underdressed.

You are advised to use layers of warm clothing and to protect extremities when exposed to extreme cold for extended periods. In the hot weather, you are encouraged to avoid strenuous exercise, avoid direct sunshine where possible and to drink plenty of fluids.

Influenza Report

Influenza season runs from mid-October through April. Each week the Centers for Disease Control in Atlanta compile reports of the level of influenza in each state.

Influenza can not be easily related to current weather or day-to-day changes because of the way it is communicated from individual to individual and because of the long incubation periods within the human body before the symptoms emerge (up to 2 weeks). However, it has been shown that the stresses on the human body brought about by extreme or changeable weather do lower the body's resistance to infection and increase the susceptibility to colds and flu.

Very cold, dry air and bright sunshine can kill airborne germs and viruses. Most of the transfer out of doors is in cloudy, wet, milder weather. More commonly, transfer is indoors between individuals in close contact.

During the flu season, increase your intakes of vitamin C, minerals such as zinc and herbs such as Echinecea which are believed to increase the body's ability to fight off attack. Avoid crowds and close contacts with sick individuals where possible during the worst epidemics.

Reflexes/Reaction Times

Reaction times are best with high and rising pressure, clearing skies and comfortable temperatures.

Reaction times (reflexes) are slowed by low or falling pressure, cloudy skies, very wet, snowy or icy conditions, extremes of temperatures or hot, dry winds. This may increase the risk of accidents for operators of automobiles and other mechanical equipment. It can also affect the performance of sports teams.

These are the same factors that cause problems with joint pain and mental function and that can induce labor. For example, when pressures fall rapidly on a chilly, damp day, the joints swell and offer more resistance to movement. When that happens, we can't respond physically as quickly even when there is no pain involved.

These weather conditions may also impair the ability to focus on a task or thought and this distraction may lead to poorer reaction times than when we are singly focused. Knowing your limitations and the limitations of others around us (like other drivers or factory workers) might help keep us safer.

Attentiveness/Mental Alertness

Mental function is best during times of relatively high pressure, comfortable temperatures and humidities. It paradoxically can also be high during major weather events such as strong thunderstorms, tornadoes or hurricanes, perhaps because of increased adrenaline flow.

Mental alertness in general is impaired when atmospheric conditions put a stress on the body. Extreme heat and cold for example can stress the body's regulatory and circulatory systems resulting in reduced mental function.

You tend to make more mistakes (e.g. more typing errors) and the quality of work diminishes (e.g. in factories there are lower production rates and poorer quality) when the environment is uncomfortable

Attentiveness in school likewise can be tied to the weather. Days with uncomfortably high temperatures and humidity produce increased restlessness in the classroom, poorer performance on tests and increases in disciplinary problems.

One possible explanation may be that we are distracted, unable to concentrate on the matter at hand because we dwell on our discomfort. Another it may in part be a circulation issue as the body's regulatory system adjusts the blood flow in order to maintain a constant body temperature. When facing extremes cold, the body's regulatory system will slow the flow of blood to the extremities to attempt to reduce heat loss. In extreme heat, the flow to the skin in greatly increased in order to attempt to maximize heat loss. The brain may somehow get shortchanged in both cases.

Be extra careful when making (take more time) important decisions under these extreme conditions. Teachers may also want to use this information to make lesson plans. If weather will make it difficult to concentrate ( e.g a hot and humid day in a school with no air conditioning), it may not be a good day to start a new topic. May be better to show a movie that day and leave the new subject to another day with more favorable and comfortable weather.

Labor and Birth Index

It has long been known that labor is often induced by falling atmospheric pressure. Hospital admissions of pregnant women reflect this. The more precipitous the fall, the greater the number of full-term and near full-term pregnant women experience labor pains. Birth follows, often near the passage of the lowest pressure or associated fronts.

The woman's body acts like a barometer – the womb is fluid sac that expands and contracts with changes in atmospheric pressure. When atmospheric pressures drop rapidly, the womb expands and exerts additional pressure perhaps triggering the labor process.

Women who are near term in their pregnancy should be sure they have the required materials and support (a ride, a packed bag, babysitters for other children) on days when the index is high.

UV Report

Sunshine has both positive and negative effects on our health and well-being. The sunshine is a mood elevator. It "brightens" our spirits.

Ultraviolet rays from the sun also activate a substance in our bodies called provitamin D and convert it to vitamin D. This vitamin prevents rickets and is especially important in growing children whose bones are still developing.

It also causes the production of melanin in the skin, which gives the skin a brown or bronze color. This serves to provide a measure of protection for the skin from damage from the sun's more harmful UV rays.

Ironically the same rays that produce these beneficial effects also cause painful sunburn and with long-term exposure, increase the risk of skin cancer. Overexposure also causes wrinkling and aging of the skin, and scientists are concerned that UV may even impair the human immune system.

The intensity of the sunshine and the degree of danger from exposure vary with the weather situation, time of year and day, latitude and altitude.

The intensity of sunshine is greatest on dry and clear days. It is also much greater in the summer and around midday. At those times, the sun is highest in the sky and the rays are most direct on the surface. In the winter and early and late in the day, with the sun lower in the sky, the rays must pass through a much greater thickness of atmosphere (double at 30 degrees above the horizon) and much of the energy is absorbed/scattered before reaching the surface.

The sun is higher in the sky and thus more intense in the tropics than in mid or high latitudes. It is also more intense at high altitudes because there is less air above to filter
out the rays.

The incidence of skin cancer in the United States has reached epidemic proportions. One in five Americans will develop skin cancer in their lifetime, and one American dies every hour from this devastating disease.

Many dermatologists believe there may be a link between childhood sunburns and melanoma later in life. Melanoma cases in this country have more than doubled in the past 2 decades, There has been an 1,800 percent rise in malignant melanoma since 1930.

Use the UV Index to decide whether to go to the beach or lake or mountains and what level of SPF protection to use. Wearing a hat on high index days is also a good idea.

Mood Index

Weather affects how we feel every day. Bright sunshine, light winds, comfortable (slightly below normal) temperatures and low humidity and high pressure give the greatest positive boost to our moods. Our outlook is like the weather, the brightest (we tend to be more optimistic) in these conditions. This is especially true if the weather had been gray and dreary for a while before the weather improved. When that happens, the fine weather is most appreciated.

On the other hand, our moods turn sour, we become edgy, restless and more likely to be pessimistic even depressed when strong storms or fronts approach with overcast skies, precipitation, low and/or falling pressures, high humidity, and strong, gusty winds. Our moods can also turn bad when hot, dry winds (like the Chinook or Santa Ana) blow. In some mid and high latitude locations, the long nights, persistent overcast and frequent storms of winter cause a more continuous mood disorder for many people.

Animals react to the changing season with changes in mood and behavior and human beings are no exception. Most people find they eat and sleep slightly more in winter and dislike the dark mornings and short days. Some have more severe bouts of feeling down all the time, low energy, problems with sleep and appetite, and reduced concentration to the point where they have difficulty functioning at work or in the home. This disorder is called SAD or Seasonal Affective Disorder (affective is a psychiatric term for mood). During the spring and summer, these people feel well and "normal".

The problems partly stem from the lack of bright light in winter. It is not a psychosomatic or imaginary illness. Researchers have proved that bright light makes a difference to the brain chemistry, although the exact means by which sufferers are affected is not yet known.

For those who suffer from this disorder, one prescribed solution is light therapy. A bright or fluorescent light for a few hours in the morning reduces winter depression symptoms, perhaps by reducing the level of the neurotransmitter melatonin, normally present at night (production and release in part triggered by low light levels). You should if possible

schedule time outdoors in sunlight each day.

Those who don't suffer from SAD, may feel the same sour mood on gray days perhaps due to the same chemical changes. They bounce back more when the weather brightens.

This product shows areas where your moods (and the moods of others) might be affected by the weather. When we show the moods to be poor, you might wish to try a herb like St. Johns Wort or Kava to improve your outlook. You certainly would want to anticipate how others might behave and adjust accordingly. For example, you might expect other drivers to be less courteous and careful and be more attentive. 

Indoor Relative Humidity

We spend most of our days indoors and thus indoor conditions are often more important than outdoor conditions. This holds true for the relative humidity.

If we don't attempt to control humidity indoors, it can cause health problems. In winter when we take the cold air outside in and heat it to 68-70F, we lower the humidity often to less than 10%.

Very low humidity in the home in winter can result in the build up of static charges as we shuffle our feet across carpets. The charge will be released when we touch other objects like doorknobs, other people, television, computers, etc. Though not dangerous it can be a shocking experience and is annoying.

More serious are the dry, itchy skin or dry sinuses and nose. Dry skin can crack and peel and will look unattractive and can lead to infections. Dry noses and sinuses may lead to a clogging or swelling and closing of the air passages and cause breathing difficulty at night In summer, the high humidity can create problems with drippy pipes, mold and mildew. Mold and mildew in the home can cause allergic reactions. It also increases our discomfort when accompanied by high temperatures.

We spend literally billions of dollars each year to control our indoor climate. Most all of our efforts and dollars are spent on controlling temperatures.

With a small additional investment we can maintain a more comfortable and healthy environment by controlling the indoor humidity.

This product computes the likely indoor relative humidity assuming no humidity controls. Use it to determine when to turn on humidifiers or dehumidifiers, or use fabric softeners in the wash, apply skin lotion or saline nose sprays.

Weather & Allergies

It has been estimated that as many as 50 million Americans suffer from allergies. For about 35 million people the culprit is some form of pollen or mold spores in the air. In addition, the 15 million people who suffer from asthma, often have their asthma provoked by airborne allergens.

The pollen comes from trees, grasses and weeds. There are also spores from molds, which grow both indoors and outdoors. Each has their peak season.

The worst day for the allergy sufferer is often the best day for the rest of us. Sunny days with dry air find the highest concentrations of pollen in the air. The wind can whip more pollen up from plants and carry it farthest. The early morning hours is often the worst time of day as the plants are busy pumping out the pollen which accumulates in the still stable, air. In the middle of the day, the pollen gets mixed into a deeper layer of atmosphere and the concentrations near the ground tend to be less. Towards dusk, as the air stabilizes again, pollen can again increase.

Rainy days on the other hand are often the best days because the rains literally wash out the pollen from the air. The relief is often short-lived. The allergens often come back strong when the weather improves. The pollen counts can rise rapidly and be joined by mold spores, which are in heavy production just two hours after the rains end.

We show the areas normally affected by tree, grass, and weed pollen during that time of the year. You can adjust locally for the winds, rain and other factors. Air filtering devices like air conditioners and air cleaners can be used when the air is pollen laden. They are especially beneficial during the night-time sleep hours.


Cardiovascular Disease


Coronary artery disease (CAD) is a condition where cholesterol plaques build up in the walls of the small coronary arteries that supply oxygen to our heart muscle. Causes of CAD are obesity, high blood pressure, high LDL cholesterol, low HDL cholesterol, smoking, diabetes, family history, sleep apnea, and possibly elevated homocysteine. These risk factors lead to a slow build up of cholesterol over a long time.

Acute coronary syndrome (ACS) occurs when one of these cholesterol plaques ruptures and its contents extrudes into the vessel, partially obstructing blood flow. This causes a thrombus (clot) to form, which completely obstructs blood flow, preventing oxygen delivery to heart muscle that the artery supplies. Subsequent death of the heart muscle is a heart attack, also known as myocardial infarction (MI).

Weather conditions can trigger an MI. Although the reasons are unclear, studies have shown the following effects:

  • ACS is more common in cold weather, especially when the air temperature fluctuates more than 14°F through the day
  • ACS is more common 24 hours after a high pressure air mass has passed
  • Most heart attacks occur during the early morning hours (6 a.m.-noon)

If you have known cardiac plaques, or are at moderate to high risk of having them, we advise the following:

  • Avoid outdoor exercise in early morning cold air.
  • Follow the Weather and Health cardiac risk index to know the high risk times when you should minimize outdoor activities.
  • Avoid shoveling snow, especially in the morning. Research has shown that exertion after only 10 minutes of shoveling snow is equivalent to a maximal stress test.